Telephone-exchange system



E. H. CLARK.

TELEPHONE EXCHANGE SYSTEM.

Patented D60. 12, 1922..

5% APPLICATION FILED FEB. 7, I919. 1.4.88, .%h

3 SHEETS-SHEET I.

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APPLICATION FILED FEB. 7. 1919. D 1 4E38 {44k latenredi Dec. 12, 1922 3 SHEETS-SHEET 2. a

E, H. CLARK.

TELEPHONE EXCHANGE SYSTEM,

APPLICATION FILED FEB. 7. 1919.

Patented Dec 12 19220 3 SHEETSSHEET 3.

Patented Dec. 12, 1922.

UNHTED STATES imam earaNr @FFHGE.

EDGAR H. CLARK, or New YORK, N. Y., AssICNo TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A, CORPORATION OF NEW YORK.

TELEPHONE-EXCHBLLIGE SYSTEM.

Application filed February 7, 1919. Serial No. 275,616.

To all whom it may concern Be it known that I, EDGAR H. CLARK, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone sys tems employing automatic switches.

The present invention is an improvement over a system disclosed in an application filed by me on October 4:, 1918, Serial No. 256,841, and has for its object the provision of an improved signaling system in which indicating devices are controlled over a pair of wires by trains of impulses of various characteristics.

In its more specific embodiment, the present invention is employed in an automatic telephone system in which calling lines terminating in'a semi-automatic telephone exchange may be connected to called lines terminating at a manual exchange. In such a system an operator at the semi-automatic exchange after connecting her answering cord to the calling line, sets one or more antomatic switches under the control of a sending device to extend the calling line to an operators position at the manual exchange. Since there is no verbal communication between the. two Operators, there must be 1 means for indicating to the operator at the manual exchange the number'of the wanted line. In the present disclosure such number is indicated by sets of lamps, a set of lamps being provided for each digit or character of the wanted number. These lamps are selectively operated in response to the sending device.

'One feature of the invention consists in the control of an indicating device by trains of impulses of varying characteristics, the separate impulses being of like character.

This and other features of the invention will appear from the accompanying drawings and description together with the appended claims. v

The drawing with F ig. 2 placed below and with Fig. 3 placed to the right of Fig. 1, diagrammatically illustrate a portion of 'a telephone system employing the present 1nvention. Fig. 1 shows a calling subscribers substationand line with brushes of the district selector at the semi-automatic operators position,,the calling plug and jack at the manual operators position and a called subscribers substation apparatus and line.

Within the small dotted rectangle at the lefthand side of Fig. 1 there are shown brushes of a cord finder switch which operates toconnect an idle sending device to a cord circuit which has been connected to the called line. Within the larger dotted rectangle at the right-hand side of Fig. 1 there are shown the operators key set and the registers of asending device for controlling the transmission actuation of the thousands, hundreds, tens and units indicating devices in the proper sequence. Fig. 3 in its lower right-hand corner shows the lamp controlling relays for indicating the thousands digit, in the lower left-hand corner of Fig. 3 the hundreds digit, at the upper left-hand corner of Fig. 3 thetens digit and at the upper right-hand corner of Fig, 3 the units digit.

In this disclosure the showing of the apparatus and-circuits .for selectingthe manual operators position has been abbreviated, but they may be of the character of the system disclosed in the patent toLundell, No. 1,168,319 of January 18, 1916, or it may be similar to the system shown in applicants Patent No. 1,334,735, issued March 23, 1920.

The trunk selecting switch referred to in the description may be of the type illustrated in the patent to Craft and Reynolds, No. 1,123,696, of January 5, 1915, although it will be readily understood that any automatic selector switch can be employed in this system without departing from the spirit of the invention.

In the description reference is made to sequence switch registers, the construction of which may be similar to that shown in the patent to Reynolds and Baldwin, No. 1,127,808 of January '9, 1915.

In general the present system comprises a set of operators keys which control se-. quence switch registers, all of which are luv of Fig. 1. A device for sending impulses as determined by the sequence switch registers is shown in the upper left hand corner of the dotted rectangle of Fig. 1 and an arrangement of relays for receiving these impulses is shown in Figs. 2 and 3.

, set of controlling relays A,

In Fig.2 there are shown two relays 201 and 202 which respond directly to the transmitted impulses. T ese relays in turn control the combination of two relays 207 and 209 which have a peculiar interaction as will be hereinafter more fully explained. A.- set of relays such as 206 and 210 is provided for each one of the digits of the called number. These relays are controlled by the. in-

teraction of the relays 207 and 209.

There is provided a set of indicating lamps for each one of the digits of the called num ber, each set of lamps bein controlled by a C and D. As shown in Fig. 3, the set A;, etc. controls the thousands lamps, the set A etc. controls the hundreds lamps, the set A? etc. controls the tens lamps and the set A etc. controls the units lamps. As shown in Fig. 2 the set A. etc. controls the stations lamps. I

The. impulses transmitted by the device controlled by sequence switch ll lin Fig. 1 are in the nature of a code, these impulses being in one train as the sequence switch 114 moves from one position to the next until it has finally reached. normal position 7 again.

llhe impulses for controlling the indication of anyone digit consists of four stages and the whole set for thes'election .of all of the indicating lamps are merged into one continuous train of twenty stages. The impulses consist of grounding neither either one or the other or both of the two linesextending from the sending device at the semiautomatic operators position to the receiv- The various combinationsareshown dia-,

grammatically in two tables as in Fig. 2,.on'e marked numerical and the other station; Thus, for instance, the trainof impulses representing the digit 7 consists in the first stage of the grounding of the tip side of the line, the second in the grounding pf both the tip and ring sides of the line, .in the third stage of the grounding of neither the tip nor 'the ring, and'in-the fourth stage of the grounding of the ring side of the line. Similarly, the trains of impulses representin the other digits and stations characters are uilt the wanted line terminates.

up with various combinations of nections.

As will hereinafter appear the lamp controlling relays A.,'-B, C and D are only energized when the tip side of the line is grounded. Thus, for instance, when-the train of impulses representing the digit 7 are transmitted, the relays'A and B only will be energized and] the realys C and D will remain unenergized. The stations code, since a smaller number of selections is to be made, never contains a grounding of the tip side of the line in the fourth stage, and therefore only three lamp controlling relays A, B and C are provided, the last stage being merely for switching purposes. 7

The particular action of the relays as ef- ..fected by the sending of these trains of impulses will be more fully explained hereafter. I

It is believed that the invention will best be understood by describing the method of,

shown at 102. When the calling subscriber removes his receiver from his switchhook,

a signal (not shown) is lighted at the. semisuch conautomatic operators position. This operator thereupon connects the cord circuit conductors 103 and 104 to the-calling line manually or by any other suitable means. As

soon as the semi-automatic. operator has connected the cord circuit to the calling line, a cord finder whose brushes are indicated at 105 and 106 operates to connect an I v for use.

When the semisautomatic operator connects the cord circuit to the calling line, she

ascertains the number of the wanted subscriber and proceeds to set u this number from the keyboard of her sen ing device. y

We will now assume that the wanted numpress the'corresponding thousands, hundreds, tens, units and stations keys, in re- '-ber is 4567-W. The operator will then del sponse to which the associated sequence switch registers will be moved. -The stations register 109 will come into position 5,-

the thousands register 110 in position 4, the

hundreds register 111 in position 5, the tens register 112 in position 6, and the units reglster 113in position 7. It will be assumed that dicated by the numerals 107 and 108 has been set to select the proper trunk for connecting the calling subscriber with the man trunk selecting switch has been moved 'into;

position 11.

After the sending device has been set, and.

the automatic trunk selecting switch whosebrushes are inwhen the trunk selecting switch has been op- 1 erated to extend the calling line to the manbrush 105, sequence switch contact 119, brush 108, lower armature and back contact of relay 120,- lower winding of repeating coil 121,

' the left-hand back contact and armature of winding of relay 123 to grounded battery.

Relays 117 and 123 are operated by current flowing over this circuit. Relay 117, by the attraction of its armature, closes a circuit from ground, armature and front contact of relay 117, winding of relay 115 to grounded battery, whereby relay 115 is energized, At the front contact and armature of relay 123, a circuit'is closed from ground, through.

relay 125, the lamp 126 togrounded battery. Lamp 126 in lighting indicates to the manual operator that a call is awaiting attention, and also indicates the trunk over which the call has been extended. The-manual operator thereupon depresses key 127 to associate the number indicating device with the trunk over which the call has been extended.

Upon the depression of key 127, a circuit is closed from ground, winding of relay 120,

contact of key 127, conductor 128, winding of relay 200 to grounded battery. Relay 200 attracts its armatures to apply ground to the various controllin leads "of the number indicating device. it the same time the relay 120 attracts its armatures, and at the lower armature and back contact interrupts the energizing circuit of relay 117. When this relay deenergizes, it closes a circuit from ground, through its armature and back contact, the armature and back contact of slowto-release relay 115, .magnet of sequence switch 114 togrounded battery, to move the sequence switch 114 out of position 1, whereupon it will, underthe control of its master contact 124, rotate through its various operating positions back to position 1, during which a complete set of impulses is transmitted to the relays 201 and 202.

In accordance with the number which we have assumed. will be indicated, that is,

4567-W, impulses will be sent over the two conductors 134 and 204 to-the relays 201 and 202, respectively, in accordance with the following table. As has been hereinbefo-re pointed out, the train of impulses consists of twenty stages, in each even one of which the ring side of the line of the conductor leading to brush 105 will be grounded. The other side of the line or that leading to the brush 106 may be grounded at any one of the stages. In the first column, the stages are numbered numerically, from ,1 to 20. In the second column, the position of the sequence switch during that particular'stage is indicated. In the third column, the stages in which the ring side of the line is grounded is indicated, and in the fourth column the stages in which the tip side of the line is grounded are'in turn indicated by the letter G.

' Position of Ring side Tip side stage gg fi of line. of line.

1 1% G 2 21; V G G 3 3}; G 4 4% G 5 5 6 6 G G 7 6% 8 75} G G Q 8!;

10 -95 c G 11 10k 12 11% G 13 12 G l4 13 G G 15 13% 16 14} G G 17 151} G 18 16?; G G 19 171} 20 18?; G

From this table it will be evident that in every even stage the relay 201 will be energized, and in every odd stage: it will be deenergized. It will also be evident that relay 202 will be energized only when the tip side of the-line is grounded, which may occur in any stage. Thus, for instance, in the first stage, relay 202 will be energized, but relay 201 will not be energized.

The action of the pair of relays 207 and 209 is controlled by the relay 201. Since the relay 201 becomes energized in eve y even position and deenergized in every odd position, there will be a recurring application of ground on the conductor 203, extended theretofrom the conductor 208 through the righthand armature and front contact of relay 201. It should be noted that the first application of ground to conductor 203 results in the energization of relay 207. The first removal of ground therefrom results in the energization of relay 209. The second application of ground thereto resultsin the denergization of relay 207 and the second removal of ground therefrom results in the deenergization of relay 209. Thus, in the sec- 0nd stage, relay 207 will be energized. In

batter and 'round. 'lhelcit-hzmd winding y front contact of relay 207, the inner leftof relay 209 ismarginal and the current flowing through these two windings in series isinsufficient to cause the energization of relay 209, but does'cause the energization of relay 207. Relay 207, inbecoming energized, extends the ground on conductor 208 through its inner right-hand armature and front contact to the right-hand winding of relay 209 which thus becomes short circuited as long as the ground is applied to conductor 203. When the third stage is reached, and relay 201 becomes deenergized and the ground is removed from the conductor 203, a circuit extending from ground at the inner righthand armature of relay 207 may be traced through the right-hand winding of relay 209, the Winding of relay 207, the left-hand winding of relay 209 to battery and ground? Current traveling through this circuitis sufficient to causethe energization ofrelay 209, and to cause the continued energization of relay 207, whereby the relay 209 becomes sufficiently energized to attract its armatures. In the fourth stage, relay 201 is againener gized and thereby applies ground to the conductor 203. In this manner the windingof relay 207 and the right-hand winding of relay 209 are short-circuited and the left-hand marginal holding winding of relay 209 is kept energized. In this manner relay 207 retracts its-armatures. When now in the fifth stage, the relay 201 becomes denergized, and the ground isremoved from the conductor .203, neither winding of relay 209 being now energized, the relay retracts its armatures.

The actions and interactions of relays 207 4 hereinbefore described in the second stage,'a ground is extended from the conductor 208 1 through the outer right-hand armature and to the winding of relay 210, which, however, is short-circuited at this time through the ap plication of ground by relay 207. In the fifth stage, when the relay 209 becomes 'deenergized,1;elay 210 becomes energized through the circuit just described 'eiztending from conductor 208, the inner right-hand armatur 1 and front contact of relay 206, winding of relay 210, winding of relay 206, to battery and ground. In the sixth stage, when relay 207 is again energized, a circuit is extended from conductor 208, the outer right-hand armature and front contact of relay 207, the inner lefthand armature and front contact of relay 210, the inner left-hand armature and back contact'of r'elay 213, the winding of relay back to normal position 1 of sequence switch 114. In the second column the condition of which indicate respectively deenergization and energization. In the third column the condition of relay 209 is similarly indicated In the fourth column, there .is a list of the counting relays as'they are in turn energized. When, for instance, relay 206 becomes energized in the third position, it remains energized until the ground is removed from con- ,80 relay 2071s indicated by the letters D and E ductor 208, as Wlll hereinafter be described.

Stage. Relay207. Relay209. gg ff 1 D 1) v 2 E 1) 20s a 11V 11 4 1) E 5 D D 210 a E B 211 r 1 E E 4 s D- E 9 1 D 1) 213- 10 11 1) 214 11 11 E 12 1) E 13 D D 215 a 14 E n 217 15 E E 16 n E 11 D 1) 21s 18 E D 219 19 E E 2o 1) E Normal po- D D .221

, sition of 1 Through theaction of relay 202 which is connected to the tip side of the line and extends through conductor 204, the upper armature and front contact ofrelay 120, brush 107, the sequence switch contact 135, brush 106, the conductor 140 to the register contacts controlled bythe sequence switches 109 to 113 inclusive, and thence to sequenceswitch contacts controlled by the sequence switch 114.

As indicated in the first table, this side of 3 the line will be grounded at various times, specifically during the first three of the first four stages. This is seen when it is remeinbered that sequence switch 109 is placed in position 5 whereby; a ground is extended through the sequence switchcontact 132 in position 1% of sequence switch 114, which is.

sequence switch 109 which is in position 5. Llkewise ground is supplied through seseouence switch contact 138 in position of the first stage, sequence switch contact 131 ofsequence switch 114 which is the second stage, through sequence switch contact 137 of sequence switch 105), and likewise through sequence switch contact 141 .in position of sequence switch 114 which .is the third stage, and thence through sequence switch contact 172 in position 5 of'sequence switch 109. In a similar manner, conductor 140 is grounded at Various stages of operation of the sequence switch 114. The effects of these groundingsof conductor 140 are shown in the energization and deenergization of relay 202. As an instance, relay 202 is encrgized in the first, second and third stages and deenergized in the fourth stage. Upon its first energization, a circuit is established from the grounded conductor 208, the lefthand armature and backcontact of relay 201, left-hand armature and front contact of relay 202, the left-hand armature and back contact of relay 207, left-hand armature and back contact ofrelay 206,.left-hand winding of relay A to battery and ground, whereby the relay A is energized. It'will thereupon lock up to the ground .onconductor 208, through its inner right-hand armature and front contact and two windings in series. In the second stage, relay 202 being energized and relay 201 now being energized, a circuit is extended from the ground on conductor 208, through the left-hand armature and front contact of relay 201, right-hand armature and front contact of relay 202, the outer right-hand armature and back contact of relay 209, the right-hand armature and back contact of relay 210, to the lefthand winding of relay B to battery and ground. Relay B thus becomes energized, and in a similar manner to relay A, locks up to the ground on conductor 208. In the third stage relay 202 is energized and relay 201 becomes deenergized. Thus, we have a ground extending from conductor 208, left-hand armature and back contact of relay 201, the left hand armature and front contact of relay 202, left-hand armature and front .contact of relay 207, the outer right-hand armature and front contact of relay 206, the outer right-hand armature and back contact of relay 211, the left-hand winding of relay C, to battery and ground, whereupon the re lay C locks up to the conductor 208 in a manner similar to relays A and B. In a similar manner, the other lamp controlling relays of the thousands, hundreds, tens and unit sets are energized. A full description of this will be found in my copending application above mentioned. From the description, it will be seen that the one set of impulses is sent over the ring side of the line which may be spoken of as aperiodicallyrecurrin set of impulses to control the relay 201, an thereby control the actions and interactions of relays 207 and 20.9, and

'202 plays no part in the control of relays 207 and 209, or the counting'relays, its sole function being to energize the lamp controlling relays when the proper circuits have been set up through the action of the counting relays. I

When the sequence switch 114 has returned to 1ts normal position and the relay 209 is finally deenergized, and the said counting relay 221 is energized, the circuits for the lighting of the 'difierent lamps are established. Through the outer left-hand armature and front contact of relay 221, a ground is placed on the winding of relay 223 which becomes energized. Through the outer right- Y hand armature and front contact of relay 219 and the outer right-hand front contact and armature of relay 221, battery is placed on the conductors 311 and 312 for lighting the lamps in the tens and units series. Through. the left-hand armature and front contact of relay 217 ground is placed on the conductor 222 for energizing relay 310, which. inv turn places battery on the conductors 313 and 314, for lighting the lamps in the thousands and hundreds series. Through the inner left-hand armature and contact of relay 200 ground is placed on the common conductor 301 for lighting the lamps in the thousands, tens and units series, and through the outer lefthand armature and contact of relay 310 ground'is extended from the conductor 208 through the conductor 315 for lighting the lamps in the hundreds Series.

ture of relay C, the front contact and outer right-hand armature of relay A, the front contact and left-hand armature of relay B to the outermost armature of relay 223 to ground. The thousands lamp 4 is included in a circuit from battery, the outer righthand armature and front contact of relay 310, the lamp 4, the next to the outermost armature andback contact of relay A, the back contact and outer lefthand armature. of relay B, front contact and inner right-hand armature of relay D to the ground on conductor 301. The hundreds lamp 5 is included in a circuit from battery, the inner left-hand armature and contact of relay 310, the outer left-hand armature and back contact of relay D the outer left-hand armature and front contact'of relay B the next to the outermost right-hand armature and back contact of relay A the lamp 5, the front contactand inner left-hand armature of relay B the next to'the innermost righthand armature and back contact of relay A the back contact and outer left-hand armature of relay C the contact and outer lefthand armature of relay 310 to the ground on conductor 208. The tens lamp is included in a circuit from the conductor-311, the inner left-hand armature andfront contact of relay D ,,the lamp 6, the front .contact and next to the outermost right-hand armature of relay A the front contact and outer left hand armature of relay B the front contact and inner right-hand armature of relay D to the ground on conductor. 301. .The units lamp 7 is included'iii a circuit from the conductor 312,the outer left-hand arma-- [ture and back contact of relay D, the outer left-hand armature and front contact of relay 'B, the next to the outermost right-hand armature and front contact of A lamp 7,, the back contact and outer right-hand armature of relay D to the ground on conductor 301. In this manner the lamps indicating the number 4567\V are illuminated.

When the operator at the manual exchange pressed the key 127 and the relays 120 and i 200 were energizedin series, the circuit for v, relay 123was opened, whereupon the armaand 104 to be connected through sequence p station 101 replaces his receiver upon itsture of relay 123 was retracted and the lamp 126 extinguished. v

As soon as the indicatinglamps become illuminated, as herein described, and the operator has the wanted number well in mind, she removes the pressure from key 127, allowing the relay 120 and the relay 200 to become deenergized. She thereupon places vplug 161'intothe jack I62 of the line No.

4567, and presses the proper ringing key to ring the station W. This action, through means not shown,.causes the conductors 103 switch contacts 165 and 164 to the brushes 107 and 108, respectively, whereby the connection is. completed and the circuit to brushes 105 and 106 discontinued. The circuit through the substation 101 energizes relays 123 and 167. The circuit through the sleeve of the jack 162 and the plug 161 enerthe relay 125, so that although the lamp 126., is now connected to the front contact of relay'125, its circuit opened at ,the'

i back contact; of relay 123. At the end. of

the conversation, when the subscriber at subhook and thereby denergizes relay 123, the

lamp 126 will be illuminated to indicate to the manual operator. that the conversation "1 has-ceased.

When relay 200 becomes deenergized, it removes the ground from conductors 208 and 3 01, whereby all of the lampcontrolling rlays which have'locked up to the conductor 301 and the counting relays which have locked-up to-conductor208 will become tie-- control said indicators.

energized and the device restored to its norphone systems or even to telephone systemsbroadly.

What isclaimed is 1. In a'signaling system, a plurality of indicators, a signaling circuit comprising two limbs, a progression switch comprising a plurality of relays, means for propagating and transmitting over one limb of said circuit a series of like impulses for successively operating said relays, and means for propagating and transmitting over the other limb of'said circuit a. second series of like impulses for selectively operating said indi cators. V v

2..In a signaling system, aplurality of indicators, a plurality of relays for controlling the operation of each of said indicators, a progression switch comprising a plurality of relays, a signaling circuit comprising two limbs, means for propagating and transmitting over one limb of said circuit a series of likeimpulses to operate said progression switch relays in,succession, and means for propagating and transmitting over the other limb of said circuit a second series of like impulses for selectively actuating said' indicator controlling relays.

3. In a signaling system, a plurality of indicators, a plurality of controlling relays for each indicator, a progression switch comprising a plurality of relays, means for propagating and transmitting over one limb of said circuit a series of like impulses for propagating an transmitting over one limb of said circuit a series of like impulses for operating all of the relays of one of said groups in succession in a fixed order, and means for propagating and transmitting over .theother limb of-said circuit a second seriessof like impulses for operating desired ones of the relays of said other group to 5. In a signaling system, a plurality of indicators, a signaling circuit comprising two limbs, two roups of relays, means for propagating am? transmitting over one limb of saidcircuit a series of.like impulses for operating all of the relays of one of said groups in succession in a fixed order, and

means for simultaneously propagating and transmitting over the other limb of said circuit a second series of like impulses foroperating desired ones of the relays of said other group to control said indicators.

6. In a signaling system, aisignaling 'circuit, a pair of circuit relays, a set of master relays, a plurality of sets of counting relays, a plurality of signal controlling relays, a plurality of sets of signals, means for periodically actuating one of said circuit relays, means responsive thereto for periodically actuating said master relays, means responsive thereto for operating said sets of counting relays in sequence, means for actuating the other one of said circuit relays means responsive thereto for actuat ing said signal controlling relays, and means responsive to said signal controlling relay means and said connecting relay operating means for actuating said signals.

In witness whereof, I hereunto subscribe my name this 30th day of January, A. 1)., 1919.

EDGAR H. CLARK. 

